You can’t ride without your horses ending up completely dehydrated? Or maybe you want to do some physical preparation before a show? In any case, you want to improve your horse’s fitness / enhance its lung capacity / work on its heart rate? Let me give you the ONLY way to success.
“My horse isn’t that much of an athlete. I went for a hack and according to the Equisense Motion S I was at canter for only 3 minutes. Yet, when I stopped the session, it was as if we had gone for a run of over 160 km. His heart rate went up to 210 bpm!! 😨 I think we’re going to have to work on my horse’s lung capacity!”
“Yeah? How do you work on lung capacity?”
“Well I’m not exactly sure… I know it’s important to improve a horse’s fitness and endurance but I’m not sure on how to proceed…”
Don’t worry, after you read this article you’ll know everything there is to know!
Peculiarities of the horses cardiorespiratory system – similarities and differences with Man
To figure out how to train a horse, we need to know how it’s made and how it works! So let’s start with a bit of anatomy.
Horses possess 1 heart ❤ and 2 lungs. This is something you already knew (I hope 😅). But horses have a few physical peculiarities you need to be aware of.
The horse’s heart
First peculiarity: horses have a gigantic heart (really)! It’s about 25 to 20 cm long and has a diameter of approximately 20 cm . In comparison, a basketball has a diameter of about 24 cm.
Weight wise it’s about 4 kg heavy which represents 0.7 to 0.9% of the horse’s body weight (depending on the race) .
In comparison, a human heart is about 12 cm long and has a diameter of 9 cm. It weighs between 280 and 300 g which represents about 0.4% of the body weight .
Let’s just say that in proportion horses beat us easily!
One last thing: their hearts are much more efficient than ours. It’s slower when resting: 28 to 40 beats per minute  when ours beat 60 to 80 times per minute .
The vet's heart vs the elite Thoroughbred's heart. Isn't it fascinating to visualize how the equine athlete has adapted so much better to high level sports!ESMP loves cardiology!
Publiée par Equine Sports Medicine Practice sur Dimanche 25 décembre 2016
If a horse’s heart rate is slower when resting, it’s actually higher than ours during an effort! A horse’s heart rate can reach 220 – 240 bpm. For us it’s (220 – age) (so about 200 bpm for a 20-year-old person). It’s important to note that horses are an exception since “usually” the bigger the animal the lower the max heart rate. But it’s not the case for horses .
During an effort a horse’s cardiac output can be multiplied by 9 to 12 to reach 400 L of blood pumped / minute while it’s only multiplied by 5 to 7 for us .
All of this makes a horse’s heart a machine of frightening effectiveness 💪. It explains why horses are athletically superior to men.
The horse’s lungs
Here as well, the lungs are very big. However and despite that the horse’s respiratory system is the biggest physiological limit to its capabilities (when we as humans are limited by our hearts).
The horse’s lungs weigh about 7 kg which represents about 1.5% of its total body weight. It’s pretty much the same in proportion to us: our lungs weigh about 850 g.
A horse’s respiratory rate when resting is similar to ours: 8 to 15 breathing movements per minute (mpm). Pulmonary ventilation when resting is however 10 times superior to ours: 66 L/min for a horse against 5,4 L/min for us.
Volume wise the horse’s lungs can store about 50 L of air when our lungs can only contain about 6 to 7 L .
However what we call “dead space” which is the air volume that comes in but is useless – it’s the sum of nostril volume and all the respiratory tubes – represents 60% of the inspired volume against 30% in our body !! This means to put it simply that 60% of the air the horse inspires is useless. 😱 That’s huge!
Other respiratory peculiarities
Horses have some other interesting peculiarities from a respiratory point of view.
Firstly, horses can’t breathe from their mouths because of the length and the mobility of their soft palate. They are then forced to breath through the nose which is pretty restricting. Furthermore their nostrils are quite small and their “respiratory conduits” are pretty thin. This creates a great resistance when the horse breathes. It has to “force” a bit more than we have to to breathe.
Secondly the horse’s respiratory rate is tied to the rhythm of its canter strides. If you listen closely the horse expires at canter when its last foreleg touches the ground. It’s because at that moment the horse “lifts its butt and lowers its head”. At that moment every viscera will be pushed on the front and press on the diaphragm which will then press on the lungs and force the expiration. It’s actually pretty problematic and it causes what we call an “hypoxemia”. This means that during intense or extended efforts the horse will lack oxygen .
To counter this lack of oxygen which could cause some big issues the horse adopts a quite unique strategy: it contracts its spleen. To be more precise the adrenaline created by the lack of oxygen will make the spleen contract and release in the blood every red blood cell it contains. These red cells will help the body receive more oxygen and give more to the muscles so they can keep moving! This way their hematocrit (the percentage of volume occupied by red blood cells in comparison to the total blood volume) is goes from 30-40% to 60-70%!!! Horses have no need for erythropoietin shots or training in altitude unlike some human athletes 🙄! 
What do we want to improve with our fitness training?
Training your horse means improving its cardiovascular system or its muscle system. You might not know it yet but you can’t improve a horse’s lung capacity.
“Horse owners often consider that training improves their horses lung capacities because they are less likely to be breathless after an effort. This happens not because the horse’s lung capacity improved but because the aerobic metabolism, the thermoregulation and the cardiovascular system were enhanced.” 
RIP then, “lung capacity”… ⚰
We are therefore going to try to improve our horse’s aerobic capacity and resistance. That is, to work on its heart rate and lactatemia (both are connected).
Impacts of fitness training on the heart rate
Regarding the heart rate, training won’t increase the horse’s max heart rate or decrease his resting heart rate (unlike it does for us) [1,3]. However on the same effort (same canter speed) the heart rate will be lower on a well trained horse. As a matter of fact the more they have to work (“momentary overloads”) the thicker the heart’s walls will get and allow it to pump harder. It enhances the oxygen flow and eventually the aerobic abilities  (one of the benefits amongst other).
Following your horse’s heart rate during an effort is therefore highly interesting when you are looking to improve your horses physique.
Impacts of fitness training on the lactates
The same way it helped with the heart rate, the fitness training will contribute to reduce the lactate concentration for the same effort. You can measure your horse’s lactatemia with a lactate analyzer but it requires to take a drop of blood directly after the effort. Not really handy on a daily basis…
Two interesting factors: V140 and V200
In the field of exercise physiology there’s a lot of talks about V140 and V200 which are indicators of the horse’s training condition. V140 or V200 represent the speed at which the horse will reach the heart rate of respectively 140 or 200 beats per minute.
The point of our fitness training is to improve these speeds (or to lower the heart rate observed at a given speed).
The advantage these indicators have is that they are “easily” obtainable (much easier than the numbers about lactates at least) and they allow you to measure objectively the impact of your training.
For example if at the beginning of the season your horse reaches 140 beats per minute at a speed of 350 meters per minute and after a month of training its V140 went up to 450 meters per minute, your work has paid off!
So how to you train your horse’s fitness? 🧐
You have to canter! Yeah, sorry… You can work on your horse’s muscles at walk and trot but improving the horse’s fitness will only work by repeated canter phases. To enhance its physical condition you’ll have to combine longer canter periods and more intense efforts!
Sorry again but there’s no performance improvement without work and without fatigue… We usually want to “preserve our horse” and in doing so we prevent our horse from reaching a level of exigence that could allow it to improve its physical condition and fitness. Wanting to preserve your horse can actually compromise its health if you try to go on an international eventing show for instance…
Effort tests as reference data
To improve your horse’s training you need to know what you’re starting with and this means you have to often have to perform tests on your horse by means of standardized tests where you have to be equipped with a GPS tracker and a heart rate monitor. Good news: our second product Equisense Motion S combines both of these features.
One of these tests consists in cantering 6 tiers for 3 minutes (from 350 to 600 meters/minute) and increasing the speed by 50 m/min every time. Between each canter session you have to walk for a minute so the horse can gather its breath and you have to trot for 5 minutes at the end for the same reason.
When you look at the Motion S data you’ll get a curve that will look like this one:
We can see here that the horse didn’t reach its V200 and that it reached its V140 on the second canter phrase at approximately 400m/min.
Be careful, this test can be really hard on horses that aren’t trained at all!! Watch out for your horse’s reactions. You don’t want to hurt your horse by rushing its training…
A fitness program to gain endurance 
Now that you know your horse’s condition better you can work on its endurance.
First, you need to impose yourself a canter session per week for 6 to 8 weeks in addition to a diverse program the rest of the week (flatwork, jumping, stretching…).
A good canter session means about 10 minutes at canter at about 400 or 450 m/min followed by 5 to 10 minutes at trot for active recovery.
Pay attention to your horse’s condition when you start with this program: 10 minutes might be too long for it! Once again you have to adjust your fitness training to your horse… In that case start with 2 minutes for a week, then 3 minutes, then 4 and increase gradually.
I actually prepared you a training program dedicated to the improvement of your horse’s fitness on the Equisense app. It includes 6 exercises to help you work on the canter gradually.
After these 6 to 8 weeks of prep work you can try the same test to see if the V140 or V200 improved or not!
- ❌ If it didn’t:
- either the training wasn’t executed properly in which case you’ll have to try again
- or your horse has physical issues that you’ll have to bring to a vet
- ✅ If however you experience an improvement of the V140 or V200 then we can move on the the next stage of the training (and this will be for another time! 😉)
💡 Key points
There are two things you need to remember:
- the expression “improving the lung capacities” is “wrong” because a horse can’t improve its respiratory capacities.
- The only way towards improving your horse’s fitness is to canter more. No choice… A first step is therefore to canter once a week for 2 to 6 minutes at about 400-450 m/min.
Now that you’ve read this you’re probably thinking “What? How insane are these guys at Equisense? I just want Princess to sweat less when we go for an active hack, I don’t want to take her on an international show!! I’m not going to buy a lactate meter and take her blood and all! Anyways I don’t have a canter track…”. And you’d be right!! Truth is it’s really hard to adjust such a program to your daily life and on the scale of a show season, albeit it’s perfectly adjusted for a professional rider. Up to you to tailor the “theory” to your expectations, your goals, your field and the resources you can put into this.
How long do YOU canter during each session?
Before you start working on this ask yourself this question: “How long do I spend at canter in each session?” . You’d be surprised! In 2017 across the entire community of riders using Equisense Motion the average canter time was… 5.30 minutes !!! 😱 Not exactly enough to work your horse’s cardio on a daily basis…
What about you?
See you soon for another article,
R&D leader at Equisense